This invention generally relates to a feeding apparatus, and more particularly, is concerned with apparatus for receiving and continuously feeding objects from successive tiered loads to a conveyor or the like.
There are numerous industrial applications wherein it is desired to feed objects off a stacked load onto a conveyor for further handling. For example, in the lumber industry rough sawn boards or cants are stacked while they air dry or are passed through a kiln and subsequently are pressed through planers or sanders for further processing. Feeders have been developed to feed boards or the like from such stacked loads onto a conveyor. A stud feeder, for example, as heretofore constructed commonly includes on one end a hoist with a lift bed and support columns for receiving a tiered load of studs from a truck. The hoist is pivotable at its base to tilt the columns toward and over a conveyor belt which leads from the feeder to a planer or sander. With the hoist tilted, the lift bed is hoisted upward along the columns of the hoist to raise the load along an angular load path toward the tops of the hoist columns. Each tier of studs slides from the lift bed as it clears the column tops onto the conveyor and is carried to the planer or sander. The bed retracts when the last tier of the load slides from it, and the hoist pivots back to a vertical position, ready to receive a successive load. With the successive load in place, the hoist again pivots and the load is hoisted upward along the load path. No studs are fed from the apparatus during the time between feeding the last tier from the preceding load and feeding the top tier from the succeeding load, a delay of about 30 seconds.
Until recent improvements in planers and sanders increased their capability, this delay between loads was insignificant compared to the time it took the planer or sander to shape the studs in an entire load. However, the high-speed planers and sanders introduced in the last several years work much faster, typically shaping an entire load of studs in about 21/2 minutes. Conventional stud feeders cannot take advantage of this capability. Thirty seconds of delay, before insignificant, now causes the planer to be idle about one-sixth of its operating time, representing a significant production loss.
One attempt to solve the problem has been to use two stud feeders and conveyors working in tandem. The two conveyors are positioned to converge at the planer. One apparatus feeds studs to its conveyor while the other receives and hoists a succeeding load so that studs are continuously fed from one conveyor or the other to the planer. But this approach is impractical for most lumber mills because of the cost. The additional area required is often not readily available in the mill and, in many cases, can be obtained only by enlarging an existing facility. Added to that is the expense of second apparatus and conveyor, which by itself doubles the cost for providing continuous feeding of studs.